One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,6)(3,7,8,4)(9,10)(11,12)(13,14)(15,16)(18,22)(19,20)(25,26)(27,31)(28,30)(29,36)(32,35)(33,38)(34,40)(37,39)(2,6)(4,7)(10,14)(11,16)(17,18)(19,23)(20,24)(21,22)(25,27,30,35)(26,31,28,32)(29,37,38,34)(33,40,36,39)(1,3)(2,4)(5,8)(6,7)(9,11)(10,15)(12,14)(13,16)(17,19,21,20)(18,23,22,24)(25,27)(26,32)(28,31)(29,34)(30,35)(33,40)(36,39)(37,38)(1,3)(2,7)(4,6)(5,8)(9,12,13,15)(10,11,14,16)(17,18)(19,23)(20,24)(21,22)(25,28,30,26)(27,32,35,31)(29,36,38,33)(34,40,37,39)(1,4,5,7)(2,8,6,3)(9,11)(10,12)(13,16)(14,15)(17,20,21,19)(18,23,22,24)(25,29)(26,33)(27,34)(28,36)(30,38)(31,39)(32,40)(35,37)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.